1. Field of the Invention
The present invention relates to a substrate assembly for a gas discharge panel, a process for manufacturing the substrate assembly, and a gas discharge panel using the substrate assembly.
2. Description of Related Art
Various types of panels have been reported to be used as gas discharge panels. Among these panels, AC-type plasma display panels (PDPs) of a three-electrode surface discharge structure have been commercialized. PDPs have been drawing attention as low-profile display devices having a wide visual angle, and the development of PDPs to high definition and large screen has been pursued to expand their use in the field of High-Vision.
FIG. 1 is a schematic perspective view of the structure of a commercialized PDP. The PDP has a front substrate assembly and a rear substrate assembly bonded together. The front substrate is so constructed that display electrodes each constituted of a transparent electrode 3 and a bus electrode 4 are arranged on a glass substrate 1 serving as a base of the front substrate assembly and are covered with a dielectric layer 5, on which is formed a protective layer 9 of MgO having a high secondary electron emission yield. The rear substrate assembly is so constructed that address electrodes 6 are arranged on a glass substrate 2 serving as a base of the rear substrate assembly so as to cross the display electrodes, barrier ribs 7 for partitioning a discharge space are provided between the address electrodes 6, phosphors 8 of red, green and blue colors are applied onto an area which is divided by the barrier ribs 7 and which covers the address electrodes 6. A Ne—Xe gas is enclosed within the discharge space formed between the front and rear substrate assemblies that are bonded together.
The dielectric layer is made mainly of a glass material and is formed by screen-printing a glass paste or laminating sheet glass. Other than the glass material, it has been proposed to use a polymer having a lower dielectric constant than that of the glass material (for example, Japanese Unexamined Patent Publication No. Hei 6(1994)-234917). Use of polymers having a lower dielectric constant can reduce a driving voltage of a gas discharge panel.
The MgO protective layer 9 is formed on the dielectric layer mainly by a vapor deposition process or a process of sputtering Mg in an atmosphere of O2. Other than these processes, there has been proposed a wet process comprising forming a film of a paste of an organic compound containing Mg such as a carboxylate of Mg by screen printing or the like and firing the film so as to remove an organic component therefrom for forming a MgO layer (for example, Japanese Unexamined Patent Publication No. Hei 9(1997)-12976). In wet processes compared with dry processes such as the vapor deposition process and the sputtering process, the manufacturing costs can be reduced because the manufacturing apparatus are not expensive and the manufacturing conditions are easily adjusted.
However, it has been difficult to simply combine a dielectric layer of a polymer having a low dielectric constant and a protective layer of an organic compound containing Mg. When they are simply combined, a problem occurs that the dielectric layer is liable to be peeled off because:    (1) the dielectric layer of a polymer deteriorates by a solvent used for making a paste of the Mg-containing organic compound, and    (2) the dielectric layer of a polymer having a great surface friction is destroyed by the solvent or by a stress generated, in the protective layer, when an organic component of the organic compound is eliminated by firing.